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1、准备创世区块文件

新建文件genesis.json 写入一下内容

{
  "nonce": "0x0000000000000042",
    "config": {
        "chainId": 101,
        "homesteadBlock": 0,
        "eip155Block": 0,
        "eip158Block": 0
    },
  "alloc": {
  },
  "timestamp": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "extraData": "0x00",
  "gasLimit": "0xffffffff",
  "difficulty": "0x10", //挖矿难度
  "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x3333333333333333333333333333333333333333"
}

2、初始化，写入创世快

将genesis.json放到下面创建的目录/data/schain/chain 下面

mkdir -p /data/schain/chain  //新建存放区块链数据目录
cd /data/schain/
geth --datadir  /data/schain/chain init genesis.json

上面的命令的主体是geth init，表示初始化区块链，命令可以带有选项和参数，其中--datadir选项后面跟一个目录名，这里为/data/schain/chain，表示指定数据存放目录为/data/schain/chain，genesis.json是init命令的参数。

运行上面的命令，会读取genesis.json文件，根据其中的内容，将创世区块写入到区块链中。如果看到以下的输出内容，说明初始化成功了。

INFO [04-17|10:14:54] Maximum peer count                       ETH=25 LES=0 total=25
INFO [04-17|10:14:54] Allocated cache and file handles         database=/data/schain/chain/geth/chaindata cache=16 handles=16
INFO [04-17|10:14:55] Writing custom genesis block 
INFO [04-17|10:14:55] Persisted trie from memory database      nodes=0 size=0.00B time=14.338µs gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [04-17|10:14:55] Successfully wrote genesis state         database=chaindata                         hash=09452d…319a20
INFO [04-17|10:14:55] Allocated cache and file handles         database=/data/schain/chain/geth/lightchaindata cache=16 handles=16
INFO [04-17|10:14:55] Writing custom genesis block 
INFO [04-17|10:14:55] Persisted trie from memory database      nodes=0 size=0.00B time=3.659µs  gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [04-17|10:14:55] Successfully wrote genesis state         database=lightchaindata

3、启动私链

geth --identity "900chain" --rpc --rpccorsdomain "*" --datadir "/data/schain/chain" --port "30303" --rpcapi "db,eth,net,web3,txpool,miner,personal" --networkid 101 --nodiscover console

启动成功 进入控制台

Welcome to the Geth JavaScript console!
instance: Geth/900chain/v1.8.3-stable-329ac18e/linux-amd64/go1.10
INFO [04-17|10:18:11] Etherbase automatically configured       address=0x316FefF2905e224f801eE2770c3672b34a36c553
coinbase: 0x316feff2905e224f801ee2770c3672b34a36c553
at block: 10 (Mon, 16 Apr 2018 13:20:49 CST)
 datadir: /data/schain/chain
 modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0
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